Respiratory Monitoring
Karten zu PACT
Karten zu PACT
Wie wird die Compliance gemessen?
Crs=Vt/Paw-(PEEP+PEEPi)
Was ist die dynamische Compliance und wie errechnet?
Cdyn = Vt/Pmax
dynamic compliance also includes the resistive (flow-dependent) component of the airways and the endotracheal tube
(erster Abfall von Pmax bis P1)
Was ist Cstat und wie gemessen?
Cstat = Vt/P2
P2 wird auch Pplat genannt
= mirrors the elastic features of the respiratory system
Was ist die Resistance?
Resistance is defined as Pressure divided by Flow V
Welche Widerstände können gemessen werden? 3
Pmax – P1/V=airway flow-dependent resistance = ‘initial’ or ‘minimal’ or ‘ohmic’ resistance RRS,init
P1 – P2/V=additional lung resistance (ΔRrs) =Pendelluft phenomenon and the visco-plasto-elastic lung and thorax behaviour
Pmax – P2/V= the sum of RRS,init and ΔRrs.
Welche Widerstände sind flow-abhängig , welche Volumen + Compliance-Abhänigig?
In clinical practice, it is important to remember that the Pmax – P1 pressure gradient is flow-dependent,
whereas P2 is affected only by variations in volume and/or compliance.
Wie lässt sich Compliance noch messen?
welche Formen?2
Annäherungsweise über Oesophagealdruck
CL = Vt/(PAO − Pes) end-inhalation − (PAO − Pes) end-exhalation
Ccw = Vt/(Pes − Patm) end-inhalation − (Pes − Patm) end-exhalation
Wobei PAO=pressure at Airways opening
Wozu sind Cl und Ccw wichtig?
Bei ARDS ist Cl erhöht
bei erhöhtem intraabd. Druck ist Ccw erhöht.
Welche Komponenten der Atemarbeit gibt es bei Unterstützer Atmung? 2
wie errechnet?
WOB performed by the ventilator (Wvent): measurements taken from the signals of Paw and respiratory system volume change (Vol).
work performed by the patient (Wpat). measurement of the pressure changes generated by the respiratory muscles. Wpat can be calculated from measurements of Pes and Vol.
Welche Komponenten der Atemarbeit gibt es bei Unterstützer Atmung? 2
wie errechnet?
WOB performed by the ventilator (Wvent): measurements taken from the signals of Paw and respiratory system volume change (Vol).
work performed by the patient (Wpat). measurement of the pressure changes generated by the respiratory muscles. Wpat can be calculated from measurements of Pes and Vol.
Wie gliedert sich Atemarbeit auf?
work = force x distance ≈ pressure x volume / 2 (Joules )
elastic work ∝ area a-b-c-a
inspiratory flow-resistive work ∝ area a-i-b-a
expiratory flow-resistive work ∝ area a-b-e-a
negative work ∝ area a-e-b-c-a (tone on inspiratory muscles during expiratory air flow)
total work ∝ Welastic + Winspiratory flow-resistive + Wnegative
passive recoil of lungs overcomes the work of expiratory flow-resistance
Was macht ein Rekrutierungsmanoeuver genau?
is a transient increase in transpulmonary pressure intended to promote reopening of collapsed or flooded alveoli.
A sustained pressure above the range of tidal ventilation is applied, and PEEP is used to prevent derecruitment.
The result should be an increase in FRC/EELV
Welche Techniken für Rektrutierung? 4
- Sustained high-pressure inflation of 40 cmH2O for 40 seconds using CPAP.
- Intermittent sighs, using three consecutive sighs at 45 cmH2O per minute for 1 hour.
- A stepwise (‘ramping’) increase in PEEP every 2 min, keeping the driving pressure constant, up to peak pressures of 45–50 cmH2O.
- Pressure-controlled ventilation (PCV) with PEEP of 25 to 30 cmH2O and peak inspiratory pressure of 40 to 45 cmH2O for 2 min.
Wie kann Rekrutierung gemessen werden?
3
- Messung des Lungenvolumens über moderne Respiratoren
- im CT
- FRC/endexp. Lungenvolumen EELV durch N2-Washout
- EELV = ΔN2 (ml)/ΔFiO2
Wie kann transpulmonaler Druck annäherungsweise ermittelt werden?
Anwendung?
Oesophagealer Druck entspricht alveolärem Druck=PEEP=transpulmonaler Druck
Wenn der alveoläre Druck bekannt st, kann PEEP daran angepasst werden
Was ist stress index?
assess the level of PEEP required to avoid over-distension. This approach uses the shape of the pressure-time curve during tidal volume delivery. Worsening compliance as the lungs are inflated (upward concavity; stress index, >1) suggests over-distension, and the recommendation is to decrease PEEP. Improving compliance as the lungs are inflated (downward concavity; stress index, <1) suggests tidal recruitment and potential for additional recruitment, thus suggesting that increased PEEP might be beneficial
Was ist stress index?
assess the level of PEEP required to avoid over-distension. This approach uses the shape of the pressure-time curve during tidal volume delivery. Worsening compliance as the lungs are inflated (upward concavity; stress index, >1) suggests over-distension, and the recommendation is to decrease PEEP. Improving compliance as the lungs are inflated (downward concavity; stress index, <1) suggests tidal recruitment and potential for additional recruitment, thus suggesting that increased PEEP might be beneficial
Gram positive Erreger? 6
Staphylokokken: koagul.neg.: St.aureus
koagul.pos.:epididermidis+saprophyticus
Streptokokken
Enterokokken
Clostridien
Listerien
Corynebakterien
Einige Gram negative Stäbchen?
Pseudomonas
Enterobacteriacea (e.coli, Enterobacter, citrobacter, Salmonellen)
Acinetobacter
Vibro
Was geschieht beim Wechsel von druckkontrollierter Beatmung auf Spotanatmung? 3
When patients begin to breathe spontaneously, intrathoracic pressure becomes negative. The consequence is that venous return and left ventricular afterload increase.
Was zeigt Iso-shunt-Diagramm?
The figure shows the effect of increasing shunt fraction (decreasing VA/Q) on PaO2 for a range of FiO2
Wie verändert sich Sauerstoffbindungskurve (SaO2/PaO2) bei Anämie?
gar nicht: Anaemia does not affect the SaO2, but only the oxygen content.
Wie errechnet sich Sauerstoffgehalt (CaO2)?
Normwert?
in Hämoglobin gebundenes O2 und physikalisch gebundenes O2
(SaO2 × Hb × 1.34) + (0.003 × PaO2 in mmHg)
% g/dl
1.34= Sauerstoffbindungskap.
0.003= Milliliter Sauerstoff, die in 100 mL plasma bei 0.135 kPa (1 mmHg) PaO2 gelöst sind
Normal arterial oxygen content is approximately 16 to 20 ml O2/100 mL blood
Wie ist Hypoxämie definiert?
a decrease in PaO2
Was hat mehr Auswirkung auf den Sauerstoffgehalt: Hb oder PaO2?
Hypoxaemia has a relatively minor impact on arterial oxygen content if the accompanying change in SaO2 is small. PO2 influences blood oxygen content only to the extent that it influences the saturation of haemoglobin with oxygen. SaO2 is a more reliable index of arterial oxygen content than PaO2. The influence of anaemia relative to hypoxaemia on arterial oxygen content is relatively greater.
Was macht exakte Aussage über Gewebsoxygenierung?
CaO2 + DO2 (Delivery, Angebot)
Berechnung von DO2?
Normwert?
Cardiac index x CaO2
DO2I = 3 × (1.34 × Hb × SaO2) × 10(=unrechung Hb) (presuming CI = 3 L/min/m2)
Normal range: 450−550 mL/min/m2
Was passiert,wenn Sauerstoffangebot nicht ausreicht?
the deprived cells must shift from aerobic to anaerobic metabolic pathways to supply their energy needs, leading to progressive lactic acidosis.
Wie kann Sauerstoffverbrauch gemessen werden? VO2
by indirect calorimetry:
a technique that uses continuous analysis of inhaled and exhaled gas flows together with oxygen and carbon dioxide concentrations to calculate VO2 and CO2 production (VCO2).
Wie kann VO2 errechnet werden?
VO2 ist die Differenz zwischen dem Produkt des inp.Volumens x FiO2 und dem expiratorischen Minutenvolumen x ausgeatemten Sauerstoffanteil
VO2 = (Vi × FiO2) − (Ve × FeO2)
Wie kann VO2 am Bett einfach gemessen werden?
Umrechung der Formel durch Haldane-Umrechung auf der Grundlage dass Stickstoff ein inertes Gas ist und damit gilt:
Vi × FiN2 = Ve × FeN2
Daraus ergibt sich vereinfachte Formel, zu der nur ausgeatmeter Fluss und O2-Konzentration benötigt wird.
Wann kann VO2 nicht sicher gemessen werden?
Leck im Kreislauf
FiO2>85%
respiration rate is >35/min
during some ventilatory modes (e.g., High frequency oscillatory ventilation, HFOV; BiPAP).
Wie kann VO2 noch annäherungsweise gemessen werden?
indirekt duch Fick'sche Gleichung:
VO2 = CardiacOutput × (CaO2 − CvO2)
The arterial–mixed venous oxygen content difference, CaO2 − CvO2, represents the quantity of O2 extracted by the peripheral tissues. Because CaO2 and CvO2 share the same factor for haemoglobin binding (1.34 × Hb), the equation can be rearranged to isolate this term:
VO2 = CO × 1.34 × Hb × (SaO2 − SvO2)
Wie funktioniert Pulsoxymetrie?
The pulse oximeter can distinguish two haemoglobin species on the basis of their different absorption of light: Oxyhaemoglobin absorbs more infrared light and less red light
deoxyhaemoglobin has an inverse pattern of absorbance.
the haemoglobin saturation is calculated as the ratio of red/infrared absorbencies.
However, not all the absorbance detected is due to arterial blood and therefore, the oximeter also determines the pulsatile component of the light absorbance signal (photoplethysmography). The change in ratio of absorption between systole and diastole can then be used to calculate the arterial saturation of haemoglobin.
Was für zu einer Fehlberechung der Sättigung? 3
Changes in pH, temperature, and 2,3-diphosphoglycerate concentration alter the PO2–SaO2 relationship
Grenzen der Pulsoxymetrie? 8
- Motion artefact (shivering, intra-aortic balloon pump and during transport)
- Abnormal haemoglobins (primarily COHb –falsely high SpO2–, and MetHb – falsely low SpO2 when SpO2 >85% and falsely high when SpO2 <85%)
- Exposure of probe to ambient light
- Low perfusion states
- Hypothermia
- Skin pigmentation
- Nail polish or nail coverings, when a finger probe is used
- Inability to detect saturations below 83% with the same degree of accuracy and precision seen at higher saturations, although the degree of discrepancy is not of clinical importance
CAVE bei Poulsoxymetrie?
At PaO2 values greater than 12 kPa (90 mmHg), SaO2 is nearly 100% and becomes virtually independent of PaO2. It is important to remember this during SaO2 monitoring; in those receiving supplemental oxygen a falling PaO2 will not be detected until PaO2 values less than 12 kPa (90 mmHg) are reached.
Was ist PetCO2?
The highest value of CO2 during the alveolar plateau is called end-tidal CO2
was sagt alpha-winkel in Kapnometrie aus?
Winkel zwischen Anstieg und Plateau: which becomes wider with increasing Va/Q mismatch
Was sagt beta-Winkel aus?
Winkel zwischen Plateau und Abfall: widens as rebreathing and anatomical/apparatus dead space increases
-
- 1 / 61
-
Flashcards
Was zeigt Iso-shunt-Diagramm?
The figure shows the effect of increasing shunt fraction (decreasing VA/Q) on PaO2 for a range of FiO2
Wie verändert sich Sauerstoffbindungskurve (SaO2/PaO2) bei Anämie?
gar nicht: Anaemia does not affect the SaO2, but only the oxygen content.
Wie errechnet sich Sauerstoffgehalt (CaO2)?
Normwert?
in Hämoglobin gebundenes O2 und physikalisch gebundenes O2
(SaO2 × Hb × 1.34) + (0.003 × PaO2 in mmHg)
% g/dl
1.34= Sauerstoffbindungskap.
0.003= Milliliter Sauerstoff, die in 100 mL plasma bei 0.135 kPa (1 mmHg) PaO2 gelöst sind
Normal arterial oxygen content is approximately 16 to 20 ml O2/100 mL blood
Wie ist Hypoxämie definiert?
a decrease in PaO2
Was hat mehr Auswirkung auf den Sauerstoffgehalt: Hb oder PaO2?
Hypoxaemia has a relatively minor impact on arterial oxygen content if the accompanying change in SaO2 is small. PO2 influences blood oxygen content only to the extent that it influences the saturation of haemoglobin with oxygen. SaO2 is a more reliable index of arterial oxygen content than PaO2. The influence of anaemia relative to hypoxaemia on arterial oxygen content is relatively greater.
Was macht exakte Aussage über Gewebsoxygenierung?
CaO2 + DO2 (Delivery, Angebot)
Berechnung von DO2?
Normwert?
Cardiac index x CaO2
DO2I = 3 × (1.34 × Hb × SaO2) × 10(=unrechung Hb) (presuming CI = 3 L/min/m2)
Normal range: 450−550 mL/min/m2
Was passiert,wenn Sauerstoffangebot nicht ausreicht?
the deprived cells must shift from aerobic to anaerobic metabolic pathways to supply their energy needs, leading to progressive lactic acidosis.
Wie kann Sauerstoffverbrauch gemessen werden? VO2
by indirect calorimetry:
a technique that uses continuous analysis of inhaled and exhaled gas flows together with oxygen and carbon dioxide concentrations to calculate VO2 and CO2 production (VCO2).
Wie kann VO2 errechnet werden?
VO2 ist die Differenz zwischen dem Produkt des inp.Volumens x FiO2 und dem expiratorischen Minutenvolumen x ausgeatemten Sauerstoffanteil
VO2 = (Vi × FiO2) − (Ve × FeO2)
Wie kann VO2 am Bett einfach gemessen werden?
Umrechung der Formel durch Haldane-Umrechung auf der Grundlage dass Stickstoff ein inertes Gas ist und damit gilt:
Vi × FiN2 = Ve × FeN2
Daraus ergibt sich vereinfachte Formel, zu der nur ausgeatmeter Fluss und O2-Konzentration benötigt wird.
Wann kann VO2 nicht sicher gemessen werden?
Leck im Kreislauf
FiO2>85%
respiration rate is >35/min
during some ventilatory modes (e.g., High frequency oscillatory ventilation, HFOV; BiPAP).
Wie kann VO2 noch annäherungsweise gemessen werden?
indirekt duch Fick'sche Gleichung:
VO2 = CardiacOutput × (CaO2 − CvO2)
The arterial–mixed venous oxygen content difference, CaO2 − CvO2, represents the quantity of O2 extracted by the peripheral tissues. Because CaO2 and CvO2 share the same factor for haemoglobin binding (1.34 × Hb), the equation can be rearranged to isolate this term:
VO2 = CO × 1.34 × Hb × (SaO2 − SvO2)
Wie funktioniert Pulsoxymetrie?
The pulse oximeter can distinguish two haemoglobin species on the basis of their different absorption of light: Oxyhaemoglobin absorbs more infrared light and less red light
deoxyhaemoglobin has an inverse pattern of absorbance.
the haemoglobin saturation is calculated as the ratio of red/infrared absorbencies.
However, not all the absorbance detected is due to arterial blood and therefore, the oximeter also determines the pulsatile component of the light absorbance signal (photoplethysmography). The change in ratio of absorption between systole and diastole can then be used to calculate the arterial saturation of haemoglobin.
Was für zu einer Fehlberechung der Sättigung? 3
Changes in pH, temperature, and 2,3-diphosphoglycerate concentration alter the PO2–SaO2 relationship
Grenzen der Pulsoxymetrie? 8
- Motion artefact (shivering, intra-aortic balloon pump and during transport)
- Abnormal haemoglobins (primarily COHb –falsely high SpO2–, and MetHb – falsely low SpO2 when SpO2 >85% and falsely high when SpO2 <85%)
- Exposure of probe to ambient light
- Low perfusion states
- Hypothermia
- Skin pigmentation
- Nail polish or nail coverings, when a finger probe is used
- Inability to detect saturations below 83% with the same degree of accuracy and precision seen at higher saturations, although the degree of discrepancy is not of clinical importance
CAVE bei Poulsoxymetrie?
At PaO2 values greater than 12 kPa (90 mmHg), SaO2 is nearly 100% and becomes virtually independent of PaO2. It is important to remember this during SaO2 monitoring; in those receiving supplemental oxygen a falling PaO2 will not be detected until PaO2 values less than 12 kPa (90 mmHg) are reached.
Was ist PetCO2?
The highest value of CO2 during the alveolar plateau is called end-tidal CO2
was sagt alpha-winkel in Kapnometrie aus?
Winkel zwischen Anstieg und Plateau: which becomes wider with increasing Va/Q mismatch
Was sagt beta-Winkel aus?
Winkel zwischen Plateau und Abfall: widens as rebreathing and anatomical/apparatus dead space increases
Wovon ist alveoläres CO2 =etCO2 abhängig? 2
- Perfusion of the pulmonary capillary bed (directly correlated to end-tidal CO2)
- Thickness of the alveolo-capillary membrane (inversely correlated to end-tidal CO2). This rarely influences CO2 diffusion since CO2 diffuses across the alveolar-capillary barrier 20 times faster than O2.
frühe und späte Zeichen der malignen Hyperthermie?
Remember the early signs of malignant hyperthermia: Masseter rigidity; Tachycardia; Hypercarbia;
Hyperthermia may be a late sign!
Was ist eine volumetrische Kapnographie?
Was wird damit gemessen?
The expired CO2 concentration is displayed against expiratory flow rate to establish the relationship between CO2 and flow.
This allows calculation of total CO2 production and respiratory dead space.
Was ist alveolärer Totraum?
A respiratory unit that is ventilated but not eliminating CO2(i.e. deprived of its blood flow) functions as alveolar dead space
Was ist Totraum?
Woraus besteht der Totraum?3
lung areas that are ventilated but not perfused
anatomic dead space (Vdanat–upper and lower airways)
alveolar dead space(Vdalv–alveoli well ventilated but receiving minimal blood flow)
Parts of the ventilator equipment (tracheal tubes, humidification devices and connectors) are considered instrumental dead space (Vdins)
Was ist der physiologische Totraum?
(Vdphys) :
sum of conducting airways (instrumental and anatomic dead space) and alveolar dead space and is usually described as the portion (or fraction) of tidal volume (Vd/Vtphys) or minute ventilation that does not participate in gas exchange
Wie kann Totraum errechnet werden?
volumetric capnography:
Enghoff modification of the Bohr equation:
Volumetric capnography simultaneously measures expired CO2 and tidal volume
Vd/Vtphys physiol. Totraumanteil= (PaCO2 − PECO2) / PaCO2
PaCO2 is arterial PCO2, PECO2 is the partial pressure of CO2 in mixed expired gas. PECO2 is equal to the mean expired CO2 fraction multiplied by the difference between the atmospheric pressure and the water-vapour pressure.
was ist x, y und z?
Was ist z+y?
X represents the expired volume of CO2 which is reflective of the volume in which there is ventilation of perfused alveoli.
Z reflects airway dead space (Vdanat) and
Y reflects alveolar dead space (Vdalv).
The areas of Z + Y reflect the physiological dead space (Vdphys).
Wie kann CO2-Volumen errechnet werden?
area between the expiratory and inspiratory curves
Wann ist der alveoläre Totraum vergrössert?
(Vdalv) is increased by
- shock states
- systemic and pulmonary hypotension
- obstruction of pulmonary vessels (massive pulmonary embolus and microthrombosis) in the absence of a corresponding decrease in ventilation
Wann ist der anat. Totraum verlängert?
2
Airway dead space (Vdanat) is increased by lung over-distension and the addition of instrumental dead space
Was ist ΔPCO2?
difference between arterial and end-tidal PCO2 (ΔPCO2)
= Hauptdeterminante bei alveolärem Totraum
Welche Gefahr besteht bei PEEP-Erhöhung bzgl Totraum?
possibility of an increase in dead space as a consequence of expanding non-perfused lung regions
Wie lautet die Berechung von SvO2?
Errechnet sich woher?
Was bedeutet eine Änderung der einzelnen Determinanten?
SvO2 = SaO2 − (VO2/1.34 × Hb × CO)
aus Fick'scher Gleichung
Was sagt SvO2 aus?
represents the amount of oxygen in the systemic circulation that is left after oxygen has been consumed by the tissues
Was sagt PVPI aus?
ratio of extravascular lung water to pulmonary blood volume
-> indirect measure of the permeability of the pulmonary vascular bed (pulmonary vascular permeability index – PVPI), thus allowing differentiation between cardiogenic (increased hydrostatic pressure) and non-cardiogenic (increased permeability) pulmonary oedema.
Warum ist plateaudruck bei vcv wichtig?
Am Ende der Inspiration kommt es zu einem Atemwegsverschluss und die Drücke gleichen sich an->Absinken bis auf einen Plateau-Druck.dieser entspricht den Drücken in den kleinen alveolen.
Welches flussmuster bei pcv?
Dezelerierend: während Insp. Passt Ventilator den Fluss kontinuierlich an so dass immer der gleiche Druck verabreicht wird.
Wie verläuft Flow-Kurve und Druck-Kurve bei pcv?
uring PCV the flow wave has the characteristic descending shape that approaches zero towards the end of inspiration. Along with the reducing flow, alveolar pressure approaches the working pressure set on the ventilator because the resistive pressure loss in patent airways is reduced
Wie können Atemwegsdrücke statisch gemessen werden?
during constant-flow, Volume-Controlled Ventilation, using the end-inspiratory occlusion technique.
During an end-expiratory pause flow drops rapidly to zero, the Vt is briefly trapped inside the lung and static airway pressure can be measured.
